One such doomsday scenario could see the asteroid trigger a mini ice age if it struck earth.

GETTY

DOOM: An ice age could be triggered if the space rock hit earth

“These would not be pleasant times”

Charles Bardeen, of the National Center for Atmospheric Research

The powerful impact would throw dust up into the atmosphere, causing average temperatures to plummet to as low as 8C globally.

The "severe global impact" would last several years, scientists say, with the world becoming a much colder and darker place.

Charles Bardeen, of the National Center for Atmospheric Research, said these cooler temperatures would be "about the equivalent of the ice ages".

"These would not be pleasant times," he warned.

NASA keeps track of any asteroids or comets that are expected to pass within 4.6million miles of the centre of the Earth – which are called "close approaches".

Top Facts About Asteroids

Asteroids are small, rocky objects that orbit the Sun. The first asteroid was Ceres, discovered by Giuseppe Piazzi in 1801. There are currently over 600,000 known asteroids in our solar system. Most asteroids are found orbiting in the Asteroid Belt, a series of rings located between the orbits of Mars and Jupiter.

1 / 10

Getty Images

There are Millions of Asteroids in the solar system, usually found in the Asteroid belt between Mars and Jupiter, however those in that pass the Earth are called Near-Earth objects